feat(claude): add switch for device profile stabilization

internal/config/claude_header_defaults_test.go

@@ -17,6 +17,7 @@ claude-header-defaults:
   os: "  MacOS  "
   arch: "  arm64  "
   timeout: "  900  "
+  stabilize-device-profile: false
 `)
 	if err := os.WriteFile(configPath, configYAML, 0o600); err != nil {
 		t.Fatalf("failed to write config: %v", err)
@@ -45,4 +46,10 @@ claude-header-defaults:
 	if got := cfg.ClaudeHeaderDefaults.Timeout; got != "900" {
 		t.Fatalf("Timeout = %q, want %q", got, "900")
 	}
+	if cfg.ClaudeHeaderDefaults.StabilizeDeviceProfile == nil {
+		t.Fatal("StabilizeDeviceProfile = nil, want non-nil")
+	}
+	if got := *cfg.ClaudeHeaderDefaults.StabilizeDeviceProfile; got {
+		t.Fatalf("StabilizeDeviceProfile = %v, want false", got)
+	}
 }